package com.albert.java_log4j_demo;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * @author 陈晖
 * @version 1.0
 * @date 2021/10/29 11:38
 * 参考连接：https://blog.csdn.net/qy20115549/article/details/83105736
 * https://leanote.zzzmh.cn/blog/post/5d1c661416199b0683002dc8
 */
public class RSAEncrypt {
    private static Map<Integer, String> keyMap = new HashMap<>();

    public static void main(String[] args) throws Exception {
//生成公钥和私钥
        genKeyPair();
        //加密字符串
        String message = "df723820";
//        System.out.println("随机生成的公钥为:" + keyMap.get(0));
//        System.out.println("随机生成的私钥为:" + keyMap.get(1));
        String gongyao = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC8+0Co5SSzPH4BZ3EAF6ziwzmCqC7iVgt7+UF22aq8kdXJHZTxW1auH74JP2h0CDeY+OUviQ9AjLONilSdTGf7N4GoKlIIA1rXoy64NtQt27KxGjZIGg48c9MPvNuxSx/n5YplgT0teoeVpt7SeyF5sydH1QPHtG5hDaRVEa+IHQIDAQAB";
        String si = "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";
        String messageEn = encrypt(message,gongyao);
        System.out.println(message + "\t加密后的字符串为:" + messageEn);
        String messageDe = decrypt(messageEn,si);
        System.out.println("还原后的字符串为:" + messageDe);
    }

    /**
     * 随机生成密钥对
     *
     * @throws NoSuchAlgorithmException
     */
    public static void genKeyPair() throws NoSuchAlgorithmException {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器，密钥大小为96-1024位
        keyPairGen.initialize(1024, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        // 得到私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

        // 得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
        // 得到私钥字符串
        String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
        // 将公钥和私钥保存到Map
        //0表示公钥
        keyMap.put(0, publicKeyString);
        //1表示私钥
        keyMap.put(1, privateKeyString);
    }

    /**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.decodeBase64(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
        return outStr;
    }

    /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @param privateKey 私钥
     * @return 铭文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str, String privateKey) throws Exception {
        //64位解码加密后的字符串
        byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
        //base64编码的私钥
        byte[] decoded = Base64.decodeBase64(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        //RSA解密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        String outStr = new String(cipher.doFinal(inputByte));
        return outStr;
    }
}
